Electrical conductors are used in a variety of situations, such as in vehicle systems, for providing power to electrically powered components and communicating information among components. Most automated assembly techniques that involve electrical conductors include cutting the wires to a desired length and stripping insulation from the ends of the wire. The exposed wire ends are eventually connected in a manner that facilitates the desired power or communication connections.
One of the difficulties associated with wire processing equipment is that it may not be possible to avoid improperly cut or otherwise damaged wires. For example, the insulation stripping blades may penetrate too deeply through the insulation and contact the wire. It is also possible that the wire is not centered within the insulation at the location where the stripping blades contact the insulation and the blades also contact the wire. It is also possible, for example, that the segment of wire that is introduced to the stripping device has a configuration that results in an unexpected alignment between the stripping blades and the wire so that the stripping blades contact the wire when the insulation is cut and stripped from the wire end. Contact between an insulation stripping blade and a wire during the stripping operation typically results in an undesirably cut or damaged wire. If the integrity of a wire end is compromised the eventual connection that is supposed to be made through that wire may be faulty.
Detecting damage to the wires during the stripping process has proven difficult for several reasons. For example machine throughput may be at a very high rate which requires a very fast response from a detection device and reliable detection may not be achievable without slowing down the wire processing machine. Additionally, the way in which wires are manipulated during the cutting and stripping process makes it difficult or impractical to attempt to establish an electrically conductive physical connection with the wire for monitoring purposes.
One attempt at detecting when a wire may have been damaged while insulation was stripped from the wire is described in the United States Published Patent Application No. US2013/0125710. That document suggests using a wired connection between the stripping blades and a control board and measuring an impedance of the stripping blades. If there is contact between the stripping blades and the conductive wire, the impedance of the conductive wire is effectively added to that of the stripping blades. The increased impedance is described as being detectable for purposes of identifying when the stripping blades contact the wire. One drawback associated with that approach is that it requires a specially designed stripping device or modification of a stripping device to include the electrically conductive connection between the stripping blades and the control board.
With the increasing amount of technology being included in vehicles, for example, there is an increasing need for wiring and more reliable connections. Current trends also include a desire to reduce the size (i.e., diameter) of the wires. It is becoming increasingly important to ensure that damaged or improperly cut wires are identified to avoid faulty or unreliable connections.